1. Field of the Invention
The present invention relates to heat sinks used in conjunction with cooling fans, and more particularly to heat sinks which facilitate flow of cooling air received from cooling fans.
2. Description of Prior Art
Modem electronic devices in a computer can operate at very high speeds. The faster an electronic device operates, the more heat it generates. Excessive heat can make the electronic device unstable, or even cause damage to the electronic device or associated components in the computer. Therefore, heat must be removed efficiently to ensure normal operation. Typically, an extruded heat sink is mounted on a top surface of the electronic device. A fan system is commonly used to facilitate heat removal by way of convection.
A conventional extruded heat sink 1 is shown in FIG. 6. The heat sink 1 comprises a rectangular chassis 11, and a plurality of fins 12 extending vertically upwardly from the chassis 11. Experiments have demonstrated that the heat sink 1 has a highest efficiency of heat removal when the thickness of the chassis 11 is in the range of 8 to 10 millimeters.
When a fan system operates at a side of the heat sink I to facilitate heat removal, a vertical side surface of the chassis 11 blocks a flow of a lower portion of cooling air generated from the fan. The cooling air moves upwardly and away from the chassis 11 and bottom portions of the fins 12 (see FIG. 7). As a result, the heat accumulating on the chassis 11 and on the bottom portions of the fins 12 cannot be speedily removed. This seriously reduces the efficiency of heat removal from the electronic device.
Thus, an improved heat sink which overcomes the above-mentioned problems is strongly desired.
Accordingly, an object of the present invention is to provide a heat sink wherein cooling air from a fan system efficiently flows through and around the heat sink.
In order to achieve the object set out above, a heat sink of the present invention comprises a chassis and a plurality of fins extending upwardly from the chassis. The chassis includes a platform and a guide portion extending horizontally from an end portion of the platform. The guide portion has top and bottom surfaces. At least one of the top and bottom surfaces is arcuate such that the guide portion tapers toward a distal end. When a fan system operates at a side of the heat sink generally facing the guide portion, the guide portion guides cooling air generated from the fan to top and bottom surfaces of the chassis and to bottom portions of the fins, whereupon the cooling air exits the heat sink. Heat accumulating on the chassis and the bottom portions of the fins is thereby efficiently removed.
Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.